Abstract: ObjectiveTo invesitgate the effect of valsartan on calcineurin signal pathway in hyptertrophied myocardium induced by pressure overloaded in rats.Methods Pressure overloaded model was established by abdominal aorta constriction.Thirty male wistar rats were divided randomly into four groups: sham-operated group, banding group, valsartan group （banding group and valsartan administation）, and PD123319 （an AT-2 receptor antagonist） group （banding group and PD123319 administration）.Serum and left ventricular myocardium Ang Ⅱ were measured by radioimmunoassays.Protein expression of u-calpain, m-calpain, calcineurin （CaN） and its phosphorylation were measured by immunoprecitipation.ResultsAng Ⅱ concentration in serum and left ventricular myocardium in banding group was higher than that in of sham-operated group, valsartan group, and PD123319 group （P＜0.01）; Ang Ⅱ concentration in serum in valsartan group was lower than that in of banding and PD123319 groups （P＜0.05）, but it was higer in left ventricular myocardium tissue （P＜0.05）.Protein expression of u-calpain and CaN phosphorylation in left ventricular myocardium tissure in banding group was higer than that in of sham-operation group（P＜0.01）.Valsartan obviously lowered their expressions in banding and PD123319 groups.Conclusion U-calpain is involved in myocardium remodeling in pressure overloaded rat model.The up-regulation of u-calpain is mediated via AT 1 and was reduced by AT 1 receptor antagonists.